Vibrational spectroscopies

Calculations of normal modes are performed with the aid of geomeTRIC [WS16].

The associated IR spectrum is calculated by default also when Raman or resonance Raman calculations are requested.

Infrared

Python script

import veloxchem as vlx

xyz="""
... 
"""

molecule = vlx.Molecule.read_xyz_string(xyz)
basis = vlx.MolecularBasis.read(molecule, 'def2-svp')

scf_drv = vlx.ScfRestrictedDriver()
scf_drv.filename = 'mol-ir'
scf_drv.xcfun = 'b3lyp'
results = scf_drv.compute(molecule, basis)

vib_drv = vlx.VibrationalAnalysis(scf_drv)
vib_drv.do_ir = True
scf_drv.filename = 'mol-ir'
vib_results = vib_drv.compute(molecule, basis)

Download a Python script type of input file to perform an IR spectrum calculation of the acroleine molecule at the B3LYP/def2-svp level of theory.

Text file

@jobs
task: vibrational
@end

@method settings
xcfun: b3lyp
basis: def2-svp
@end

@vibrational
do_ir: yes
@end

@molecule
charge: 0
multiplicity: 1
xyz:
...                     
@end

Download a text file type of input file to perform an IR spectrum calculation of the acroleine molecule at the B3LYP/def2-svp level of theory.

Raman

Python script

import veloxchem as vlx

xyz="""
... 
"""

molecule = vlx.Molecule.read_xyz_string(xyz)
basis = vlx.MolecularBasis.read(molecule, 'def2-svp')

scf_drv = vlx.ScfRestrictedDriver()
scf_drv.filename = 'mol-raman'
scf_drv.xcfun = 'b3lyp'
results = scf_drv.compute(molecule, basis)

vib_drv = vlx.VibrationalAnalysis(scf_drv)
vib_drv.do_ir = False
vib_drv.do_raman = True
vib_drv.filename = 'mol-raman'
vib_results = vib_drv.compute(molecule, basis)

Download a Python script type of input file to perform a Raman spectrum calculation of the acroleine molecule at the B3LYP/def2-svp level of theory.

Text file

@jobs
task: vibrational
@end

@method settings
xcfun: b3lyp
basis: def2-svp
@end

@vibrational
do_raman: yes
@end

@molecule
charge: 0
multiplicity: 1
xyz:
...                     
@end

Download a text file type of input file to perform a Raman spectrum calculation of the acroleine molecule at the B3LYP/def2-svp level of theory.

Resonance Raman

Python script

import veloxchem as vlx

xyz="""
... 
"""

molecule = vlx.Molecule.read_xyz_string(xyz)
basis = vlx.MolecularBasis.read(molecule, 'def2-svp')

scf_drv = vlx.ScfRestrictedDriver()
scf_drv.filename = 'mol-reson-raman'
scf_drv.xcfun = 'b3lyp'
results = scf_drv.compute(molecule, basis)

vib_drv = vlx.VibrationalAnalysis(scf_drv)
vib_drv.do_ir = False
vib_drv.do_raman = True
vib_drv.filename = 'mol-reson-raman'
vib_results = vib_drv.compute(molecule, basis)

Download a Python script type of input file to perform a resonance Raman spectrum calculation of the acroleine molecule at the B3LYP/def2-svp level of theory.

Text file

@jobs
task: vibrational
@end

@method settings
xcfun: b3lyp
basis: def2-svp
@end

@vibrational
do_resonance_raman: yes
frequencies: 0.05-0.10 (0.05)
@end

@molecule
charge: 0
multiplicity: 1
xyz:
...                      
@end

Download a text file type of input file to perform a resonance Raman spectrum calculation of the acroleine molecule at the B3LYP/def2-svp level of theory.